The scientific mission of the Phoenix Epidemiology and Clinical Research Branch (PECRB) is to determine the etiology of type 2 diabetes mellitus as it occurs among Pima Indians of Arizona. This population of Native Americans has the highest reported prevalence and incidence rate of this disease of any population in the world. We have used several different scientific approaches to find the cause of the disease including (1) epidemiologic; (2) clinical physiologic; and (3) molecular genetic approaches. In few other laboratories in the world are scientists from these diverse backgrounds working together to apply the latest techniques in each discipline to solve a single problem. Working closely with Pima Indian volunteers the branch has made substantial progress in identifying physiologic and genetic determinants of diabetes risk factors. In addittion, several clinical trials have been conducted to intervene in the natural history of this disease to prevent it and its severe complications. The branch welcomes new investigators to work in the field, in the clinical research center, and/or in the basic laboratories to help develop new ideas and strategies to achieve our scientific goals and to ultimately prevent this disease.